Projector pen

ABSTRACT

A small device for projecting images from a video generating device such as a computer, television receiver, or similar device onto a screen or other surface is described in this invention. The device is the size of the pen, and converts video instructions using a processing unit and memory into light signals that are projected. In the one embodiment, the device uses pulsed laser light from red, green, and blue lasers that are combined into a single light pulse that is transmitted through a rotating disk containing numerous lenses that transmit each light pulse to a specific location on the screen.

FIELD OF INVENTION

This invention relates to the projecting of images from a computer, atelevision receiver, or other similar device onto a screen or wall, andin particular addresses a miniature device for projections.

BACKGROUND

For thousands of years, man has tried various methods to communicatewith groups of people, in classrooms, meetings and large groups. Formost of the time, a speaker used his voice and hand movements tocommunicate with his audience. But this had it limitations, particularlyin regards to technical data. So the next step was to use paper chartsand diagrams that the speaker could flip through to provide his audiencewith detailed data. This had the problem of being particularly bulky anddifficult to move between locations.

The next advancement involved the use of overhead projectors and foilslides. For most of the latter half of the twentieth century, mostmeeting rooms contained an overhead projector. These projectorscontained a high wattage light bulb below a flat topped lens. The bulbprojected light through the lens and through the speaker's foil. Thelight then traveled through another set of lenses and a mirror, thatturned the image 90 degrees for projection onto a screen or othersurface. The speaker prepared a set of foils that contained hispresentation information. These foils were either hand drawn or printedon a laser printer.

This method had the disadvantage that the slides were not easy to changeon the fly, and could be hard to rearrange in the middle of apresentation. As a result, there was a great need to find a moreconvenient method of directly projecting presentations onto a screen.

The solution came in the form of LCD projectors. These projectorsconnected directly to the computer, typically using the external monitorport on the computer. The computer generates the image and transfers theimage to the projector. The projector then uses a high powered bulb toconvert the image into light. The white light from the bulb is splitusing dichroic mirrors into red, green, and blue light beams that aredirected to small LCDs that allow or disallow portions of the light beamto proceed to a dichroic combiner cube. The dichroic combiner cubereassembles the red, blue and green light beams into a combined beam.This is then projected through a lens to the screen or wall.

However, these devices have the disadvantage of being heavy and bulky.Even the best devices weigh 2-4 kilograms (roughly 4-8 pounds) and cantake up the volume of a ream of paper. A lighter and more portablesolution is needed. Something of a size and weight that can easily becarried in a pocket or a briefcase. But the current technologies can notbe made small enough to fit in such a package. This invention addressesthe abovementioned problem.

FIGURES

FIG. 1 shows a picture of the projector pen device.

FIG. 2 show a drawing of the projector pen device in use.

FIG. 3 shows and internal drawing of the positioning of the internalelements of the projector pen.

FIG. 4 is a functional diagram of the electrical components of theprojector pen.

FIG. 5 is a diagram of the rotating disk assembly.

FIG. 6 shows the path of light through the projector pen.

FIG. 7 show the path of light through the rotating lenses.

SUMMARY OF THE INVENTION

A light projecting device, packaged in a container no more than 5centimeters (2 inches) wide and 5 centimeters (2 inches) high,consisting of an interface (that could wired or wireless) for connectingthe light projecting device to a video generating device (the videogenerating device could be a computing device or a television receiveror similar device) where the interface receives instructions (eitherdigital or analog) from the video generating device that specify a videoimage where the instructions processed by the light projecting device,such that the video image is projected from the light projecting devicein a format such that the video image is visible on a surface.

In another embodiment, the above invention contains a clip for clippingthe device to a pocket.

In another embodiment, a system for projecting an image on a screen orother surface, consisting of a video generating device for generatinginstructions for a video image where the video generating devicetransmits instructions to a light projecting device (packaged in acontainer no more than 5 centimeters (2 inches) wide and 5 centimeters(2 inches) high), where the instructions are processed by the lightprojecting device, such that the video image is projected from the lightprojecting device in a format such that the video image is visible on asurface.

A light projecting device consisting of a wired or wireless interfacefor connecting the light projecting device to a video generating device(the video generating device could be a computing device or a televisionreceiver or similar device) where the interface receives instructionsfrom the video generating device that specify a video image where theinstructions processed by the light projecting device, such that thevideo image is projected from the light projecting device in a formatsuch that the video image is visible on a surface, where the device ispowered by a battery when the interface is disconnected.

DESCRIPTION

FIG. 1 shows a drawing of the projector pen 101. In one embodiment, thisdevice is small, perhaps the size of a pen, with a length of 15centimeters (about 6 inches) and a width of 1 centimeter (about ⅜^(th)inch). This device would weigh about 400 grams (around 14 oz). Theintention is for the device to be easily carried in a pocket or in abriefcase without taking much room or adding much additional weight.

The projector pen 101 is supported on a table or desk by two legs 104and the anterior base of the projector pen 101, near the cable 102. Thecable 102 attaches to the projector pen 101 on the lateral side of theanterior of the device. This cable 102 may be a USB, Firewire (IEEE1394), Ethernet (with or without power over Ethernet) or similar cable,and may be wired directly into the projector pen 101 or may connect to aconnector at the end of the projector pen 101. One type of connector onthe projector pen 101 may be a type B mini-USB connector oralternatively an RJ-45 Ethernet jack.

In another embodiment, the cable could be a video cable using a standardinterface such as S-Video; RCA Video; 15-Pin VGA, or similar.

The other end of the projector pen 101 contains a mechanism for allowinga video image 103 to be transmitted from the projector pen 101.

The legs 104 and the base of the projector pen 101 that sit on the tablehave feet made of rubber or similar material to prevent slippage of thedevice during operation and to provide stability of the image. The legs104 could be mounted directly on the projector pen 101 and the legs 104could telescope to adjust the vertical location of the projected imageon the screen 202. Alternatively, the legs 104 could snap onto theprojector pen 101 anywhere along the length of the device to adjust thevertical location of the display. Or the telescoping legs 104 could bescrewed into the projector pen 101.

The anterior end of the projector pen 101 has a soft rubber base forsupporting the back end of the projector pen 101 on a table.Alternately, this rubber base could have a ball bearing mounted pivot toallow for adjusting the angle of the projector pen 101 depending uponthe location of the screen 202.

In an alternate embodiment, the projector pen could be mounted to theside of a personal computer 201, a laptop or a personal data assistant(PDA) such as a Palm Trio or similar device.

Alternatively, the projector pen 101 could be mounted using a ball mounton top of a pedicle, similar to the old pedicle pens. The pedicle wouldprovide a stable base for the projector pen 101, and the ball mountwould allow adjustment of the direction of the projector pen 101. Theball mount should be stiff enough to prevent unintended movement yetflexible enough to allow adjustment. In this embodiment, one or morefunctions of the projector pen 101 could be transferred to the pedicle.The pedicle would be used to add stability to the projector pen 101.

FIG. 2 shows the projector pen 101 in use. The projector pen 101 isconnected to a computer 201 via a cable 102. The computer 201 createsthe image and transfers the image via the cable 102 to the projector pen101. The projector pen 101 converts the digital image into a video image103. This image is projected to a screen 202. Alternatively, the imagecould be projected onto a wall or any other surface.

In an alternative embodiment, the projector pen 101 may be connected tothe computer 201 through a wireless interface. The wireless antennacould be installed inside of the projector pen 101, or the antenna couldbe designed inside a clip on the outside of the projector pen 101. Thisclip could be similar to a ball point pen clip, and used to clip theprojector pen 101 to a shirt pocket. In this embodiment, the power forthe device could be supplied by one or more batteries 307 or through apower cable.

One advantage of the battery embodiment is that a presentation could bedownloaded into the memory 401 of the projector pen 101, and theprojector pen 101 could be used independently of the computer 201. Inthis embodiment, buttons would have to be added to the projector pen 101to enable the user to cycle through the images stored in memory 401. Thebattery embodiment could be used with a wireline or wireless interface.

The buttons in the battery embodiment (buttons could be used in anyembodiment) could be mounted to the side of the projector pen 101 (or onthe base of a pedicle embodiment). Buttons could enable the projectorpen 101 to be turned on and off, another button could tell the projectorpen 101 to move to the next image in memory, and a third button couldtell the projector pen 101 to move to the previous image in memory.

The computer 201 could be a standard personal computer. The computer 201could have a separate monitor or could use the projector pen 101 as themonitor. The computer 201 has a CPU and memory, and typically, but notnecessarily, could have a mass storage device such as a disk drive andcould have a network connection.

Typically, the computer 201 would be running a program for creatingvideo images for display, such as Microsoft Powerpoint, Windows MediaPlayer or similar program.

Alternatively, the computer 201 could be replaced by another videogenerating device such as a television receiver. The television receivercould either receive wireless signals or through cable or DSL wirelineconnections.

The projector pen 101 can also serve as a display device for a PDA. Thisis very convenient for a businessman to use his PDA to drive aPowerPoint presentation through the projector pen 101, instead of usinga heavy laptop and LCD projector.

FIG. 3 shows the internal functionality of the projector pen 101.Starting with the entry of data and power signals near the anterior endof the device, the signal and power enter the projector pen through theconnection 301. The connection 301 could be a mini-USB connector foraccepting a USB cable. The signal comes in the connector and isprocessed by transceivers. After being received, the signals aretransmitted to the CPU assembly 302 for processing.

The power also comes into the unit via the USB cable 102. The power isfiltered to remove power spikes and is then split into the propervoltages for powering the CPU assembly 302, the rotating lens 305, andthe laser assembly 303. In order to simplify the power supply design andminimize the size of the projector pen 101, every effort is made tomaintain a single voltage requirement for all components. For example,by choosing a CPU assembly 302 with a 5 volt DC requirement to match thevoltage available on the USB cable, power will not have to be converted.5 volt DC semiconductor laser diodes 403, 404, 405 and a 5 volt DC motorto drive the rotating lens 305 could also be used. By matching all othercomponents to a single voltage, size and complexity of the power supplycan be reduced. USB cables can provide up to 500 mA at 5 VDC.

The projector pen 101 could also include batteries 307 to allow theprojector pen to display images when the projector pen 101 isdisconnected from a power source. This may be useful in applicationswhere a computer 201 is not available. The batteries 307 could also berechargeable to eliminate the need to open the projector pen 101 toremove the batteries 307.

Alternately, the projector pen 101 could be powered by a separate powercable that is connected to an AC power transformer. This transformerwould connect to the 110 AC power in from the electric power grid, andconvert the power to the power level required by the projector pen 101.

The CPU assembly 302, in one embodiment, is a single system on a chipdesign with logic cells to incorporate the decoding of the USB protocoland converting the information received into signals to energize ordeenergize each of the three lasers 403, 404, 405 in the laser assembly303. The CPU assembly 302 also takes an input from a sensor 407monitoring the rotating lens 305 so that the firing of the lasers 403,404, 405 can be synchronized to the location where the lens will directthe light.

There are a number of possible sensor devices 407 that could be used forthis purpose, from a magnetic sensor to a mechanical sensor. Onepossible sensor would be a photo sensor 407 that detects laser lightreflected from a small mirror 503 on the rotating disk 502.

Because of the high speed data requirements to display a mediumresolution video image on the screen 202, the CPU assembly 302 may bedesigned to include a DMA 402 path to move data from the memory 401 tothe laser assembly 303. For XGA resolution of 1024×768 pixels refreshedat 60 times per second, one bit of data must be sent to each of thethree lasers 47 million times per second. For UXGA resolution of1600×1200 pixels, the data must be sent to the lasers 115 million timesper second.

The laser assembly 303 is electrically connected to the CPU assembly 302(more specifically, the DMA 402 ports of the CPU chip 302). The CPUassembly 302 determines when each laser 403, 404, 405 provides light.The light from the laser assembly 303 is sent towards the screen 202.

Mechanically, the laser assembly 303 is located next to the connector301. This is to put the weight of the lasers as close to the anteriorend of the projector pen 101 as possible.

One embodiment includes three lasers 403, 404, 405 that provide threedifferent colors to combine into a combined light pixel 604. Thisprovides 2³ or 8 different colors per pixel. To increase the number ofcolors, the intensity of each laser 403, 404, 405 can be adjusted byvarying the intensity of the beam by pulsing the laser at varying rates.On some lasers, the power can be reduced to reduce the intensity of thebeam. With either method, the number of colors can be increased to anylevel depending upon the design of the video circuitry within the CPUassembly 302 and depending upon the amount of memory 401 available forthe video in the CPU assembly 302.

Alternatively, the lasers 403, 404, 405 could be replaced with three(one red, one green, and one blue) high intensity lights or a singlelight could be used that passes through a diachronic prism to split thelight into red, green, and blue light beams.

Once the light beams leave the lasers 403, 404, 405, the three lightbeams are combined in the combining optics 304 (see FIG. 6 for moredetail) into a combined light beam 604 containing the red, green, andblue light elements from the lasers 403, 404, 405. The combined lightbeam 604 is then moved off center to a location parallel to the lengthof the projector pen 101 close to an edge.

The combined light 604 exiting from the combining optic assembly 304next passes through the rotating lens assembly 305 that is designed tobend the light to the precise location on the screen 202 for thatparticular pixel. The image is formed by sending each burst of lightfrom the laser to a location on the screen 202 in 1/60^(th) of a second.As such, the rotating lens assembly 305 rotates 60 times per second,powered by a small electric motor 501. The rotating lens assembly 305 isdesigned with 768 lenses 504 mounted on a circular disk 502 for XGAresolution or 1200 lenses 504 for UXGA resolution. Each lens 504 willbend the combined light 604 from the combined optics assembly 303 acrossa line on the screen 202. The next lens 504 is offset slightly lowerthan the previous lens so that the following line is displayed on thescreen 202 just below the previous line.

Throughout this specification examples are used based upon the UXGAvideo specification. Any other video standard could be substituted byreplacing the number of lenses, lines, pixels, and colors describedherein with the appropriate parameters from the desired video standard.

The rotating lens assembly 305 contains a sensor 407 to locate the topleft hand corner of the image and to signal the CPU assembly 302 so thatthe rotating lens assembly 305 can be synchronized with the laserassembly 303.

The lens 306 then focuses the light beam and directs the light beam fromthe rotating lens 305 to the screen 202.

FIG. 4 shows the electrical flow of information through the projectorpen 101. Video and other information enters the projector pen 101through the connection 301 and is then transferred to the CPU assembly302. The video information is transferred by the CPU 406 into memory 401either directly or after being reformatted for DMA transfer to thelasers 403, 404, and 405. Other instructions received by the projectorpen 101 are processed by the CPU 406 and entire CPU assembly 302 asnecessary.

Once the video data is in memory 401, the DMA circuitry 402 will takethe information from the memory 401 and transfer the information to thered laser 403, green laser 404, and blue laser 405. There are a numberof different schemes that could be used to perform this transfer. Forinstance, the memory 401 could be structured in 48 bit words, with 16bits assigned to each of the red 403, green 404, and blue 405 lasers.The 16 bits could be used to direct each laser to transmit light at oneof 65,535 different intensity levels.

Another scheme could use the pulsating nature of the lasers to regulatethe intensity, by using the color specific intensity information topulse the laser to vary the intensity.

The CPU assembly 302 also receives information from the sensor 407 thatsynchronizes the location of the rotating lens disk 502. The CPUassembly 302 uses this information to direct the DMA 402 to startsending the information to the lasers 403, 404, 405. Because therotating lenses 305 determines where the each bit of light (each pixel)is placed on the screen 202, the rotating lens disk 502 must besynchronized with the lasers 403, 404, 405.

The rotating lens assembly 305, as seen in FIG. 5, is responsible formoving pulses of light from the three lasers 403, 404, 405 to 1600×1200different locations on the screen 202. Each pulse directed to a fixedlocation on the screen 202. This is done with a disk 502 that has 1200different lenses 504 (shown as a representation, the actual disk 502will have many more lenses 504 than are actually drawn on FIG. 5) placedin a circle near the outer edge. Each lens 504 is offset slightly fromits predecessor so that it focuses the combined light pulses 604 oneline below the line generated by the previous lens. As the rotatinglenses 504 turn, the light from the lasers 403, 404, 405 is first bentby a lens 504 to sweep across a line, creating a full line of pixels onthe screen 202. The next lens 504 displays the next line. This processcontinues for a full rotation of the disk 502, passing 1200 lenses 504and displaying 1200 lines of light on the screen 202.

The design of the lasers 403, 404, 405 is such that 1600 pulses of lightare sent through each lens 504 during each rotation of the disk 502,creating 1600 pixels for each line. In an alternate design, the lasers403, 404, 405 could be left on if the subsequent pixel has the sameintensity, effectively displaying a line of light on the screen 202.

The rotating lens disk 502 is spun by a motor 501 at 60 rotations persecond so that the screen is refreshed 60 times per second. This willassure that the human eye sees a complete picture on the screen 202 andthat movement or images on the screen 202 seem natural.

The rotating lens disk 502 also has a sensor 407 to detect the positionof the disk 502. The sensor 407 is a photo sensor that will detect thereflection of the laser light off a small mirror 503 mounted on the disk502. The mirror 503 will reflect the combined light 604 from thecombined optics assembly 304 back to the photo sensor 407. The mirrorwill also provide a brief gap in time to allow the CPU 406 to setup theDMA 402 for the transfer of the next frame.

FIG. 6 shows the path of the light through the combined optics assembly304. Red light 608 generated from the red laser 403 passes through amirror 605 and then is then sent through a second mirror 601 thatdirects the light parallel to the side of the projector pen 101. Greenlight 609 from the green laser 404 passes through mirror 606. The redlight 608 is then combined with the green light 609 at the dichroiccombiner 602 into a combined red-green light 603. Similarly, the bluelaser 405 directs the blue light 610 through a mirror 607 to thediachronic combiner 602 a. The red-green light 603 is then combined withthe blue light 610 at the second dichroic combiner 602 a to form thecombined (red-green-blue) light 604. This combined light is then sent tothe rotating lens assembly 305.

In another embodiment, the lasers 403, 404, and 405 could be mountedsideways to direct their light to the side of the projector pen 101directly at the mirror 601, and the diachronic combiners 602 and 602 a.The order of the lasers is not important in this invention, and could becombined in any other order.

FIG. 7 demonstrates the movement of the light through the rotating lens305 assembly. A first pulse of combined light 604 a from the combingoptics assembly 304 moves through the first lens 504 a (mounted on therotating disk 502) and is bent towards the right-most position of thetop line of the image 703 a. The combined light 604 a is then focusedthrough the final lens 306 to the left-most position of the top line.About 10 nanoseconds later, a second pulse of combined light is sentthrough the first lens 504 a and is bent towards the position (aftergoing through the final lens 306) of the second pixel location on thetop line of the image 703 a. Later, combined light pulses 604 b and 604c hit the first lens 504 a and are bent towards their respectivepositions on the top line of the image 703 a. Each pulse of combinedlight 604 a, 604 b, 604 c originates at the same location and travelsthe same path until it reaches the lens 504 a on the disk 502. The disk502 is rotating and lens 504 a is moving. As each pulse of combinedlight 604 a, 604 b, 604 c reaches the lens 504 a, they are bent to theappropriate position on the top line of the image 703 a (after beingflipped by the final lens 306). Final lens 306 is stationary.

Once the top line of the image 703 a is complete, the second lens 504 bmoves into position, and combined light pulses 604 d, 604 e, 604 f aredirected through the lens 504 b towards the second line of the image 703b. Second lens 504 b is offset slightly from first lens 504 a such thatit directs the light to the location of the next line of the image. Thiscontinues for each pixel on each line of the complete image.

In another embodiment of the invention, the signals from the computer201 or television receiver could be in the form of analog video signalsfrom a S-Video, RCA Video, 15-Pin VGA or similar interface that aretransferred directly to circuitry that drive the laser assembly 303. Inthis embodiment, both the CPU assembly 302 and the batteries 307 wouldbe optional.

The forgoing descriptions of various embodiments of the invention havebeen presented for purposes of illustration and description. It is notintended to limit the invention to the precise forms disclosed. Manymodifications and equivalent arrangements will be apparent.

1. A light projecting device comprising an interface for connecting thelight projecting device to a video generating device; said interfacereceiving instructions from the video generating device that specify avideo image; said instructions processed by the light projecting device,such that the video image is projected from the light projecting devicein a format such that the video image is visible on a surface; whereinsaid light projecting device is packaged in a container no more than 5centimeters wide and 5 centimeters high.
 2. The light projecting deviceof claim 1 wherein the container is substantially cylindrical with adiameter of no more than 5 centimeters.
 3. The light projecting deviceof claim 1 wherein the container is substantially elliptical with adiameter of no more than 5 centimeters.
 4. The light projecting deviceof claim 1 wherein the container has a length of no more than 20centimeters.
 5. The light projecting device of claim 1 wherein the videoimage projected by the light projecting device is capable of changingbased upon the instructions.
 6. The light projecting device of claim 1wherein the video generating device is a computing device.
 7. The lightprojecting device of claim 1 wherein the video generating device is atelevision receiver.
 8. The light projecting device of claim 1 whereinthe interface is wireless.
 9. The light projecting device of claim 1wherein a clip for holding the light projecting device to a pocket isconnected to the container.
 10. The light projecting device of claim 1wherein the instructions are analog signals.
 11. A system for projectingan image comprising a video generating device for generatinginstructions for a video image; said video generating devicetransmitting said instructions to a light projecting device; saidinstructions processed by the light projecting device, such that thevideo image is projected from the light projecting device in a formatsuch that the video image is visible on a surface; wherein said lightprojecting device is packaged in a container no more than 5 centimeterswide and 5 centimeters high.
 12. The system of claim 11 wherein thecontainer is substantially cylindrical with a diameter of no more than 5centimeters.
 13. The system of claim 11 wherein the container issubstantially elliptical with a diameter of no more than 5 centimeters.14. The system of claim 11 wherein the container has a length of no morethan 20 centimeters.
 15. The system of claim 11 wherein the video imageprojected by the light projecting device is capable of changing basedupon the instructions.
 16. The system of claim 11 wherein the videogenerating device is a computing device.
 17. The system of claim 11wherein the video generating device is a television receiver.
 18. Thesystem of claim 11 wherein the interface is wireless.
 19. A lightprojecting device comprising an interface for connecting the lightprojecting device to a video generating device; said interface receivinginstructions from the video generating device that specify a videoimage; said instructions processed by the light projecting device, suchthat the video image is projected from the light projecting device in aformat such that the video image is visible on a surface, wherein thelight projecting device is powered by a battery when said interface isdisconnected from said video generating device.
 20. The light projectingdevice of claim 19 wherein the container is substantially cylindricalwith a diameter of no more than 5 centimeters.
 21. The light projectingdevice of claim 19 wherein the container is substantially ellipticalwith a diameter of no more than 5 centimeters.
 22. The light projectingdevice of claim 19 wherein the interface is wireless.
 23. The lightprojecting device of claim 19 wherein a clip for holding the lightprojecting device to a pocket is connected to the container.